✔ 最佳答案
Black holes (黑洞) are very cold, NOT hot.
The temperature of a black hole with mass the same as the mass of the Sun is only one ten-millionth of a degree above absolute zero (i.e. 10^-5 K). A black hole about the mass of the Moon has a temperature of 2.7 K
Since black holes are very massive objects, their densities are very very high. For black holes with the same mass as the Sun, the densities could reach 1.8 x10^16 g/cm^3.
References:
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971111e.html
http://en.wikipedia.org/wiki/Hawking_radiation